Monitor or TV to play video games. ?

What is best for PC and Xbox gaming a dedicated Monitor or is a TV just as good ? and what do I need to look for spec wise

Computing and gaming is my sons thing ( much to my annoyance ) but he is running around with the Scout's right now, so it's not all bad. He is getting the monitor/ TV for his Birthday and seems to think a dedicated monitor is best, I was thinking that a TV would be more flexible and that the manufacturers put more effort into tv's. It will be a combined present from us, Grandma and uncles so I reckon around £200 ish.

HD TVs have the same resolution as monitors now, which is usually higher than the xbox games, most are 720p anyway. Just about all 1080 TVs will work as a monitor too. 1080p as opposed to 1080i seems most favoured.

Have one for my Son's Xbox but don't think he has watched TV on it ever!

Reckon I'd go for a monitor if it was PC gaming though because I bet they have a better refresh rate. Although plasma is supposed to be best for console games because of the contrast.